Countershaft brake



April 24, 1951 1 H. J. FINDLEY COUNTERSHAFT BRAKE Filed March 11, 1949 5 Sheets-Sheet 1 p IN VEN TOR.

' A OW/WD J F/Awur A ril 24, 1951 Filed March 11, 1949 H. J. FINDLEY COUNTERSHAFT BRAKE 5 Sheets-Sheet 2 INVILJNTOR. Han Aw fi/vmir BY My 7 A ril 24, 1951 H. J. FINDLEY 2,550,545

COUN TTTTTTTTTTT KE Filed Ma rch 11, 1949 eats-Sheet 5 YINVENTOR. Harm/e0 J. /://VOZY ATTOR/VIKS Patented Apr. 24, 1951 Howard .J. Findley,

Eaton Manufacturing Ohio, a corporation of Ohio Application March 1.11, 194d. Serial No- 80,901 .6 Glaims. (Cl. 192- 4 This-invention relates to, gear -ratio change power transmitting gearing and particularly to the braking or retarding thereof for shifting.

Broadly the invention comprehends the provisionof .a power absorption braking or retarding mechanism of the magnetic type arranged in association with the gearingof a power transmittin eaiting mechanism for retarding the rotation :of certain gear elements thereof so. as to permitof .thereasy change speed gear shifting operation of the power transmitting mechanism.

An object .of the invention is the provision of power absorption braking or retarding mechanism adapted to be associated with a change speed .vehicle transmission or the like for quickly retarding the rotation of the countersha'ft thereof to permit of afast shifting of the transmission gearing from one speed ratio to another.

Another object of the invention is the provision of any electromagnetic power absorption mechanism for .use as a braking apparatus for effectively quickly-retarding the operational rotation of thecountershaft of a change speed gear power transmission, said power absorption mechanism being controlled for operation by appropriate switch means arranged in the electrical current supply therefor.

A further-object of the invention is the proyision ofv an electromagnetic power absorption mechanism utilized as .a braking means for retarding the rotation .of the countershaft of a vehicle change speed transmission effective to provide for ease in the shifting of the gears of the transmission especially through the shifting up phase. thereof, said power absorption mechanism being supplied electrical current from a suitable source. and said supplied current being controlled by the operation of a switch in thecurrent supply Iineiadapted to be actuated by the normal movement of. the vehicle clutch pedal.

it yet further obj ectof the invention is the pro,- yision of an electromagnet c power absorption braking means for retarding the rotation of the countershaft of a vehicle transmission incidental to the shifting thereof wherein theelectrical current supply to the braking means can be modulated and manual y, foot or otherwise controlled providing .for the desired amount of retardation of rotationof the countershaft for a proper shift whenever required.

other objects and, advantages of .the invention will appear from the following description taken in connection with the of he. specification. and in which:

5 Fig. 1 is a side plan view of a conventional drawings forming a part Chardon, Ohio, assignor to Company, Cleveland,

2 type of transmission. having a power absorption braking or retarding mechanism associated therewith;

Fig.2 is a fragmentary cross-sectionalized view of the power absorption braking or retarding mechanism of Fig. .-1 illustrating its gear intermeshing relation with thetransmission;

Fig. 3 is a fragmentary partially cut-away end p an .view of Fig. 2.;

ofanother power absorption braking or retardingmechanism as applied directly upon the coun tershaftof the transmission of Fig. .l as an alter native to the arrangement shown thereby;

Fig 5. is.a diagrammatic illustration of an electrical current supply circuit for controlling the operation of the. power absorption braking .or re.- tarding mechanisms of Fig, 2 and Fig. 4; and

Fig. 6 is .a diagrammatic illustration .of a meritfled form of electrical current supply circuit for controlling the operationof the power absorption braking mechanisms of Figs. ,2 and 4.

The present invention is directed at the movi ionof braking .means adaptable to change speed transmissions and the like for effectively, quickly retarding the rotation of the countershaft thereof permitting of ease in shifting of the transmission and wherein it isdesirable to modulfate the braking force as well as effectively control the operation .of the braking means. The braking means herein utilized take the form of eddy current electromagnetic power absorption mechanisms .and preferably those of the combination eddy current magnetic fluid. type thereby permittins of .the use of .a mechanism of small size yet effective to accomplish its required function.

As herein employed, the braking means is either mounted upon or geared to the countershait of the transmission with it is to .be associated such thatupon the energization of the electromagnetic coil means thereof the brake effects .a retardation of the countershaft and the gearing forming a part thereof thus allowing for the shifting and intermeshing of the respective gears for -a desired change speed gear operation of the transmission.

The requirement for retardation of the countershaft of a chan e speed transmission incidental to. the shifting of the transmission especially in upsh-i-fting is essential with regards to heavy duty vehicles wherein the oountersha-ft will not nor mally sufficiently quickly slow down when it is desired to perform a shifting of the transmission gears from one speed ratio to another.

As a means of controlling the operation of; the

Fig. 4 is a fragmentary cross-sectionalized view braking means, the electrical current supply circuit is provided with switch means adapted to be either manually or clutch pedal actuated. Rheostatic control means can also be provided either alone or in conjunction with the aforesaid switch means for modulating the amount of braking desired. The rheostat can be adjustably preset or be adjustable to alter the speed of the braking action depending on the condition of the lubricant in the transmission case and its normal retarding effect upon the countershaft.

Referring to the drawings for more specific details of the invention, I represents generally a change speed transmission comprising a power input shaft I2 adapted to be driven from an engine, not shown, through a conventional clutch, not shown, adapted to disengage the engine from the transmission, a countershaft I4 and a power output shaft I6. The transmission proper is enclosed in a transmission housing I8 and has associated in geared relation therewith a power absorption braking means 28, the purpose of which will hereinafter appear.

The input shaft I2 has provided on one end thereof a hub 22 having external gear 24 and clutch element 26 as integral parts thereof, gear 26 being arranged axially extending from external gear 24, whereas the output shaft I6 which is arranged concentrically to the input shaft has arranged in splined relation thereon gear 28 adapted to mesh with gear 30 aflixed to countershaft I4. A gear member 32 having an external gear 34 and a clutch element 36 integral therewith is mounted for rotation upon output shaft I6.

7 The countershaft I4 has afiixed thereto in addition to gear 38, gears 38 and 40 adapted to mesh respectively with the external gear 24 and external gear 34. A shiftable gear member 42 having internal clutch elements 44 and 46 thereon is splined for axial movement upon the output shaft I6, clutch element 44 being adapted to mesh with external clutch element 26 and gear 46 with external gear 36, said gear member 42 adapted to be shifted to one position to cause meshing engagement between gear 26 and clutch element 44 or to another position to cause meshing engagement between gear 36 and clutch element 46 or it can be shifted to rest axially between the clutch elements 26 and 36 and thus be inactive for the transmission of power therethrough.

Braking means is of the eddy current magnetic fluid type and comprises a stationary member 48 suitably mounted on the transmission housing having an electromagnetic coil 58 mounted thereon adapted to be supplied electrical current from a suitable source such as a storage battery 52, and a drum member 54 rotatably mounted on the supporting shaft 56 for member 48 arranged in circumferential enclosing relation thereto. The eddy current magnetic fluid mechanism hereinutilized is more fully described and illustrated by my co-pending application Serial No. 97,269, filed June 4, 1949, noW Patent No. 2,519,449, dated August 22, 1950. The drum member 54 in cooperation with the stationary member 48 is adapted to retain a magnetic fluid therebetween, said fluid being operable in connection with the energization of the coil between the drum and stationary member to increase the torque holding or braking capacity therebetween. The drum member 54 has a gear 58 fixedly mounted thereon having meshing engagement with external gear 24 of input shaft I2.

Fig. 4 illustrates the arrangement of a braking means 68 similar in most respects to the braking means 20 as an alternative to the gear meshing relation of braking means 20 and comprising a stationary member 62, a coil 64, a source of electrical current 66 for the coil, and a rotatable drum 68, the hub 10 of which is fixedly secured as an extension upon countershaft I4 for rotation therewith. I

In normal operational use of either of the braking means 28 or 68 in association with transmission I0, the rotatable drum members thereof are adapted to rotate in direct relation therewith, that is, the drum member 54 through the meshing relation of gears 48, 24, and 38 to countershaft I4 and drum member 68 as an integral part of the countershaft. The drum members 54 and I58 each form the medium of relation between the transmission and the respective braking means 28 and 68.

For the purpose of explanation, the operational use of braking means 28 will suflice for braking means 60.

Normally with the rotation of countershaft I4 as induced by the engine rotation transmitted thereto from the input shaft I2 by way of gears 24 and 38 or from the rotation of the vehicle wheels imparted thereto through any of the various gearing meshing between the output shaft I4 and countershaft I6, the drum member 54 rotates conjointly therewith. The drum member normally does not impose any load on the countershaft other than the negligible frictional resistance of the magnetic fluid material interposed between the drum and stationarymembers which can be discounted for all material purposes.

With the rotation of the countershaft in the normal state of its transmitting power from the input to the output shafts and the requirement to perform a shifting operation from one established gear shift position to another that is, for instance, from 1st to 2nd or 2nd to 3rd it becomes necessary, to effect a quick shift, to retard the rotation of the countershaft thereby permitting of a proper, easy intermeshing gear change. This requirement for shifting is exceedingly necessary in the case of a heavy duty vehicle in the course of negotiating an uphill grade because otherwise if no braking was imposed on the countershaft permitting of a quick easy shifting from one gear ratio to another, the vehicle might fail to negotiate the grade with possible serious results. The countershaft rotation is effectively retarded through the energization of the coil 58 associated with stationary member 48 of braking means 20 wherein the magnetic flux created between the stationary and drum members together with the intersection of the magnetic fluid contained therebetween imposes a drag or braking force upon the driven members, this drag in turn being imparted throughgears 58, 24, and 38 to the countershaft to retard same and permit of an easy shifting between the various gears of the transmission in the up shifting thereof.

As illustrated by Fig. 5 the coil 50 of the braking means 28 is supplied electrical current through an electrical circuit 18 having battery 52 as a part thereof. The current supply to the coil is controlled by a, make and break switch mechanism 12 adapted to be actuated by a clutch pedal 14 associated with the clutch of the vehicle having the transmission I8 incorporated therein, and a rheostatic switch 16 for adjusting and/or presetting or altering the speed of the braking action by effectively modulating the flow of current to the coil.

clutch pedal as to be actuated solely upon the I pedal being fully depressed so as to minimize the possibility of operating the braking means in downshifting at which time there is no necessity of retarding the rotation of the countershaft.

Fig. 6 illustrates a modified form of electrical circuit I3 from that shown by Fig. 5 wherein solely a rheostatic form of switch 80 is provided for controlling the flow of current to the braking means. In this manner the brake can be solely manually controlled as requirements for its use arise.

While this invention has been described in connection with certain specific embodiments, the principle involved is susceptible of numerous other applications that will readily occur to persons skilled in the art.

What I claim is:

1. In combination with a change speed power transmission comprising an input shaft, an output shaft, a countershaft and gearing on the respective shafts intermeshing with one 1 another for transmitting power from one shaft to the other, and a magnetic braking device comprising a stationary member, a rotatable member associated therewith coupled to the countershaft, a magnetic fluid sealed between the stationary and rotatable members; and means for controlling the cooperation of the device for inducing a braking action upon the rotatable member.

2. In combination with a change speed power transmission, an electromagnetic braking device comprising a stationary member affixed to the housing for the transmission, a rotatable member associated with the stationary member being coupled to a power transmitting element of the transmission, a magnetic fluid sealed between the stationary and rotatable member operable therebetween, an electromagnetic coil afilxed to one of the members, and an electrical circuit supplying current to the coil comprising a source of current, a pedally actuated make and break switch and a manually actuated variable resistance switch.

3. In combination with a change speed power transmission, an electromagnetic braking device comprising a stationary member ailixed to the housing for the transmission, a rotatable member associated with the stationary member being;

coupled to a power transmitting element of the transmission, a magnetic fluid sealed between the stationary and rotatable members operable therebetween, an electromagnetic coil .afiixed to one of the members and an electricalcircuit supplying current to the coil comprising a source of current and a switch for controlling the supply of current to the coil.

4. In combination with a vehicle change speed power transmission, an electromagnetic braking device comprising a stationary member, a rotatable member associated therewith affixed to a power transmitting element of the transmission, a magnetic fluid between the stationary and rotatable members operable therebetween, and an electromagnetic coil aflixed to one of the members, a vehicle clutch pedal, and an electrical circuit for supplying current to the coil comprising a switch adapted to be actuated by the clutch pedal upon the normal full operation thereof and an adjustable rheostatic switch.

5. In combination with a vehicle change speed transmission, an electromagnetic braking device comprising a stationary member affixed to the housing for the transmission, a rotatable member cooperable therewith aflixed to a power transmitting element of the transmission, a magnetic fluid sealed between the stationary and rotatable members, and an electromagnetic coil affixed to one of the members, a vehicle clutch pedal, an electrical circuit for supplying current to the coil and a switch for the circuit actuated bythe clutch pedal when the clutch pedal is fully depressed.

6. In combination with a change speed power transmission, an electromagnetic braking device comprising a stationary member afiixed to the housing for the transmission, a rotatable.[-member associated with the stationary member being coupled to a power transmitting element of the transmission, a magnetic fluid sealed between the stationary and rotatable members operable therebetween, an electromagnetic coil aflixed to one of the members and an electrical circuit supply- I ing current to the coil comprising a source of current, a make and break switch and a variable resistance switch.

HOWARD J. FINDLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number I Name Date 973,187 Foss Oct. 18, 1910 1,230,896 Haupt June 26, 1917 1,739,946 Carhart Dec. 17, 1929 Doman Mar. 29, 1932 

